From a75248d2cfe77f64b72e893e2d9a242acbaaf75b Mon Sep 17 00:00:00 2001
From: Tyler McMullen <tyler@fastly.com>
Date: Mon, 4 Dec 2017 16:03:04 -0800
Subject: [PATCH] Move the initial stack pointer adjustment to after the CSR
 pushes.

---
 cranelift/filetests/isa/intel/prologue-epilogue.cton | 6 +++++-
 lib/cretonne/src/isa/intel/abi.rs                    | 8 ++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/cranelift/filetests/isa/intel/prologue-epilogue.cton b/cranelift/filetests/isa/intel/prologue-epilogue.cton
index edbe90cbc5..df0bf28ff0 100644
--- a/cranelift/filetests/isa/intel/prologue-epilogue.cton
+++ b/cranelift/filetests/isa/intel/prologue-epilogue.cton
@@ -4,12 +4,14 @@ set is_compressed
 isa intel haswell
 
 function %foo() {
+    ss0 = local 168
 ebb0:
     return
 }
 
 ; check: function %foo(i64 fp [%rbp], i64 csr [%rbx], i64 csr [%r12], i64 csr [%r13], i64 csr [%r14], i64 csr [%r15]) -> i64 fp [%rbp], i64 csr [%rbx], i64 csr [%r12], i64 csr [%r13], i64 csr [%r14], i64 csr [%r15] native {
-; nextln:     ss0 = incoming_arg 48, offset -48
+; nextln:     ss0 = local 168, offset -216
+; nextln:     ss1 = incoming_arg 48, offset -48
 ; check: ebb0(v0: i64 [%rbp], v1: i64 [%rbx], v2: i64 [%r12], v3: i64 [%r13], v4: i64 [%r14], v5: i64 [%r15]):
 ; nextln:     x86_push v0
 ; nextln:     copy_special %rsp -> %rbp
@@ -18,6 +20,8 @@ ebb0:
 ; nextln:     x86_push v3
 ; nextln:     x86_push v4
 ; nextln:     x86_push v5
+; nextln:     adjust_sp_imm -168
+; nextln:     adjust_sp_imm 168
 ; nextln:     v11 = x86_pop.i64
 ; nextln:     v10 = x86_pop.i64
 ; nextln:     v9 = x86_pop.i64
diff --git a/lib/cretonne/src/isa/intel/abi.rs b/lib/cretonne/src/isa/intel/abi.rs
index 89c24787f6..ad85a8e0af 100644
--- a/lib/cretonne/src/isa/intel/abi.rs
+++ b/lib/cretonne/src/isa/intel/abi.rs
@@ -234,10 +234,6 @@ fn insert_prologue(
         RU::rbp as RegUnit,
     );
 
-    if stack_size > 0 {
-        pos.ins().adjust_sp_imm(Imm64::new(-stack_size));
-    }
-
     for reg in csrs.iter() {
         // Append param to entry EBB
         let csr_arg = pos.func.dfg.append_ebb_param(ebb, csr_type);
@@ -248,6 +244,10 @@ fn insert_prologue(
         // Remember it so we can push it momentarily
         pos.ins().x86_push(csr_arg);
     }
+
+    if stack_size > 0 {
+        pos.ins().adjust_sp_imm(Imm64::new(-stack_size));
+    }
 }
 
 /// Find all `return` instructions and insert epilogues before them.